Penicillin - discovery

In contrast to the sulfa drugs, which were
deliberately developed from a series of industrial chemicals, the first
antibiotic was discovered by accident.

Alexander Fleming, a Scottish physician
and bacteriologist, almost tossed out some culture plates that had been contaminated
by mold. Fortunately, he took a second look at the curious pattern of growth on
the contaminated plates. Around the mold was a clear area where bacterial
growth had been inhibited. Fleming was looking at a mold that could inhibit the
growth of a bacterium. The mold was identified as Penicillium notatum and later
renamed Penicillium chrysogenum. In 1928 Fleming named the mold's active
inhibitor penicillin. Thus, penicillin is an antibiotic produced by a fungus.
The enormous usefulness of penicillin was not apparent until the 1940s, when
it was finally tested clinically and mass produced.